From b34e526e92a81118b323e48ec5db966b9a5e7280 Mon Sep 17 00:00:00 2001
From: Philip Yang <Philip.Yang@amd.com>
Date: Thu, 26 May 2022 16:15:38 -0400
Subject: drm/amdkfd: Use mmget_not_zero in MMU notifier
Git-commit: fa582c6f3684ac0098a9d02ddf0ed52a02b37127
Patch-mainline: v5.19-rc2
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
MMU notifier callback may pass in mm with mm->mm_users==0 when process
is exiting, use mmget_no_zero to avoid accessing invalid mm in deferred
list work after mm is gone.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 2ebf0132c25b..3bd0f1a670bb 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -2307,6 +2307,8 @@ svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
if (range->event == MMU_NOTIFY_RELEASE)
return true;
+ if (!mmget_not_zero(mni->mm))
+ return true;
start = mni->interval_tree.start;
last = mni->interval_tree.last;
@@ -2333,6 +2335,7 @@ svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
}
svm_range_unlock(prange);
+ mmput(mni->mm);
return true;
}
--
2.38.1